In general, an electromagnetic wave is a type of energy generated by using electricity, and means composite wave of electrical field and magnetic field.
Also, the electromagnetic wave is not material but energy in view of physical science, because it has not mass or temperature, and is not visible. However, it is harmful to the human body. When a human body is exposed to the electromagnetic wave, the human body is affected by the electromagnetic wave. For example, when the distribution of Na ion and K ion through cell membrane is changed by the electromagnetic wave, secretion quantity of the hormone (melatonin) in the human body is reduced, and the body temperature is raised. Also, according to the research of WTO, the electromagnetic wave having very low frequency of 0˜1000 Hz and low frequency of 1˜5000 KHz is generated when AC power generating the frequency of 60 Hz is used in home. Therefore if the human body is exposed to the electromagnetic wave for a long time, the human body becomes weak due to the change of body temperature and biorhythm.
Accordingly, the human body must be protected from the electromagnetic wave generated by electronic and electrical devices, appliances, instruments and machines in order that a person does not take a disease. In particular it is very important to shield the electromagnetic wave in electric devices such as an electric warmth device including electric blanket or floor paper, a health auxiliary device including a warmth lumbar band, and a warmth vest or a warmth cushion which are used in directly contact with the human body, and electronic device such as a computer and so on.
It is described below for the problems of the traditional warmth device.
In general, the warmth device includes a warmth wire therein and shielding material surrounding the warmth wire to shield the electromagnetic wave generated from the warmth wire. The shielding material guides the electromagnetic wave to the ground. If the electromagnetic wave is not guided to the ground, the human body is directly affected by the electromagnetic wave.
Japanese Utility Model Publication No. 3016977 has disclosed an electromagnetic wave shield device that shields the leakage of the electromagnetic wave from the electric and electronic devices by detecting the ground terminal from the terminals of AC power and connecting the devices to the ground terminal.
However the conventional electromagnetic wave shield device further needs a ground detecting apparatus for detecting the ground terminal to guide the electromagnetic wave to the ground terminal. However, because the ground detecting apparatus has a complicated construction, it has a problem raising cost in manufacturing.